This invention relates generally to the removal of heat from electronic circuit components, and more particularly an improved construction for conducting heat from components, mounted on a common panel or board, to a panel support structure.
Electronic component generated heat may be transferred from the component to its surroundings by convection, radiation, or conduction. Heat may be transferred directly from the component by convection where any of its surfaces are exposed to a surrounding fluid, either liquid or gas. However, direct contact of the cooling fluid with the component may contaminate the component and influence its electronic functions or inhibit maintenance procedures. U.S. Pat. No. 4,138,692 avoids the contamination aspect by placing a heat conducting stud in direct contact with the component, with the stud extending through a bellows into the cooling fluid. The resulting construction is cumbersome and not well suited to edge mounted circuit panels in a stacking arrangement.
Heat may be transferred directly from a component by radiation from any of its surfaces to cooler surrounding surfaces. However, the low component operating temperatures required for high reliability of electronic operation causes heat radiation to be small.
Heat may be conducted directly from a component through its electrical leads or connectors, e.g., the component can be mounted astride the heat transfer material or heat transfer device. An example of this is provided by U.S. Pat. No. 4,118,756 wherein a heat pipe device having conduction bars extending between the electronic components and the supporting circuit panel. The specific design of the conducting bars must be coordinated with the electronic design to insure that the heat conduction paths do not interfere with electrical circuits, hence each electronic module, or component becomes a unique design problem. An additional shortcoming in that arrangement has been identified as an increase in shock and vibration sensitivity because of the increased lead lengths necessary to span the heat pipe bars and subject to the mass of the component.
Still another shortcoming or disadvantage of a between panel and component location for the heat transfer or conduction means is that it cannot be adapted to use with components of the type wherein the component is designed to rest directly against the panel surface and electrical connections are made at locations around the peripheral, bottom edge of the component.